Sanitary Mixer Mechanical Seal

Agitator Lip Seals

Pharmaceutical and biotechnology companies may encompass some of the most challenging sealing applications in industry. Although temperature, pressure, and chemistry may not, at first glance, be as aggressive as a chemical plant in Houston or an off shore oil platform, the requirements to avoid product contamination, provide ease of cleaning, and run with little or no cooling / lubrication make these applications a real challenge for seal designers. Further, with new products / processes being developed all the time, temperature and pressure requirements continue to become more severe. Below we will examine some of the solutions Terrapin Process Inc. applies to these applications.

First, we would like to address some of the standards and terminology used when describing these applications:

What is a Sanitary Seal? The answer to this question depends upon the application. It can range from a simple single spring component seal to an elaborate double cartridge seal. Basically, it is a seal that meets the cleaning requirements of the process. This can encompass SIP (steam in place), CIP (clean in place), autoclaving, or a complete disassembly / cleaning.

What is available fast and cheap? The simplest seal design would be a single spring component seal. These seals typically employ a dynamic elastomer boot to seal along the shaft and drive the rotary portion of the seal. The stationary face is either mounted in an elastomer �cup� or �boot� or sealed with an o-ring on the OD. Metal parts are often 304SS, with 316 / 316L SS available as a special order. A range of face materials will be available for the application, but elastomer choice is often limited. �Slippery� elastomers such as Teflon or FFKM cannot be used due to the need for the elastomer to drive the rotary section of the seal. Documentation available is often limited to CoC�s.

Typical Single Spring Component Seal

What if my product / process has more stringent requirements? Moving up from the basic single spring component seal brings a number of options. We can provide a cartridge seal (all seal components are pre-set and installed on a sleeve that slides onto the pump shaft) or a more specialized component seal. The design flexibility at this price / delivery point allows us to use virtually any seal face or o-ring material. We can also offer complete documentation packages including USP Class VI certification for o-rings and mill certificates for metal components.

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Cartridge Seal	Component Seal Designed with FDA Materials / Doc�s

What if my product / process has very specific requirements? No problem! We specialize in custom seal applications. We can engineer / build a seal to fit your specific equipment / process. At this point, we can employ your choice of metal(s), o-rings, faces, etc. Debris wells can be incorporated to avoid any seal face shedding from falling into the product. Ports / drains can be incorporated into the seal design for cleaning solutions. Polished surfaces are available to help that cleaning solution do its job, as well as, drainable o-ring grooves and sloping surfaces. Full documentation packages are available including USP Class VI certification for o-rings and mill certificates for metal components.

Conceptual Drawing of Seal with Debris Well

Other Applications: Note that we can supply seals for a wide variety of equipment / applications. These can include extremely high temperatures, cryogenics, dry powders, and more.

What is USP Class VI and What Other Standards May Apply to My O-Rings? USP Class VI: This is the most stringent of the USP (U.S. Pharmacopeia) test standards. It involves preparing extracts of the test material in saline, alcohol, polyethylene glycol, and vegetable oil which are implanted into rabbits or rats and compared to a control (USP Class V). Class VI then adds an implantation test, where a strip of the test material is implanted into a rabbit and observed for not less than 120 hours. USP Class VI is common in the medical device industry and certification is often required for o-rings in seals.

ISO 10993: This is a set of harmonized standards for medical device testing, that is accepted in the US, Europe, and Japan. Included are tests for:

• Cytotoxicity (ISO 10993-5)
• Sensitization (ISO 10993-10)
• Irritation / Intracutaneous Reactivity (ISO 10993-10)
• Acute System Toxicity (ISO 10993-5)
• Subchronic Toxicity
• Genotoxicity (ISO 10993-3)
• Implantation
• Hemocompatibility (ISO 10993-4)
• Chronic Toxicity
• Carcinogenicity
• Reproductive / Developmental

Testing under ISO 10993 is generally more stringent than under USP Class VI. Also, items tested under ISO 10993 will often only be tested under the applicable category for the intended application. Therefore, the end use of the material must be known prior to testing.

I already have seals, can you still help me? Absolutely. We offer complete repair services for all manufacturers and models of seals. We will evaluate your seal, quote the repair, and then proceed under your instructions. The seal will be returned, in as new condition, with certificates for any parts changed / installed.

Our experts stand ready to serve your sanitary sealing needs. Please contact us with your needs: